Osaka Expo Parking Question

Going to the Expo tomorrow but we're coming from outside of Osaka. I tried to book parking too late online. Coming in by public transport is too much of a hassle and it is raining tomorrow.

Could I park at a parking lot that is maybe a few train stations away from the Expo? Can anyone recommend a parking lot a few stations away? We are planning on arriving at 10:00. Our Expo tickets are from 11:00. Thanks in advance for any responses.

by Father-of-Hayk